**Eligibility and registration **

There are two official age groups: pre-university, and university. Anyone who qualifies for the next IPhO qualifies also for the pre-university age group. All BSc and MSc students of any university qualify for the university age group.

**To register, please fill this form: ****Physics Cup 2025**

If you cannot access the registration link due to country-specific restrictions, please send your registration data (full name, date of birth, e-mail address, country, school or university, age group (university/pre-university), physics teacher (if pre-university) by email to physcs.cup@gmail.com.

**Publication of the problems, hints, and results**

Problems and Hints are published on Sundays at 13:00 GMT. Once a problem has been published, the first hint will be posted two weeks later, on a Sunday at 13:00 GMT. After that, a new Hint will be added every Sunday until there are no more Hints left. Intermediate results will be published on a weekly basis, every Sunday at 13:00 GMT. Solutions will be accepted up to two weeks after the last Hint is published. Sometimes the final deadline for a problem is extended, such extensions will be announced together with the intermediate results. Faster solutions and solutions submitted before hints are posted will receive higher scores, see below. The final results for each problem will be published within a couple of weeks of the final deadline.

**Submitting the solutions**

All solutions are to be sent by email to **physcs.cup@gmail.com**. Please use the subject line “Problem No 1” (“Problem No 2”, etc), exactly as written here; the phrase “Problem No” anywhere within the subject line triggers an automatic reply confirming your submission. You are advised to submit the answer as fast as you can, but not later than the final deadline of the problem (usually around 7 weeks from the publication). Since there is a speed bonus, you can first submit only the answer. In that case, you need to submit a full solution within the next 48 hours (failing to do so invalidates your answer-only submission).

**Accepted formats**

LaTeX, PDF, MsWord, jpg. You can scan (or take a photo) of your hand-written solution, or write it in LaTeX (recommended) or MsWord. You can produce also a semi-LaTeX text – a simple text file/e-mail using LaTeX syntax for formulae (e.g. m=m_0/\sqrt{1-v^2/c^2}).

**Grading**

**The base score for each problem is 1.0 pts** if no hints have been published by the submission time; **each published hint reduces the base score by 0.1**. If you earn a bonus or a penalty, the base score will be multiplied with appropriate factors. Either a full or zero credit is given; on a weekly basis, on Sundays, the competitors are notified if their solutions are correct, “almost correct”, or incorrect. “Almost correct” stands for solutions with minor mistakes, e.g. a typo leading to an incorrect numeric prefactor. If the solution was not correct, contestants can continue sending new solutions until they manage to fix all mistakes; however, each “almost correct” solution incurs a penalty factor of 0.9, and each incorrect solution — a penalty factor of 0.8. The penalty will be smaller if the contestant detects the mistake by himself/herself, and submits a corrected solution before receiving a notification: 0.95 and 0.9, respectively.

**The first 10 correct answers** (supplemented later with a complete solution) **receive a bonus factor** according to the formula k = 1.1^{11−n}, where n is the order number. The best solution will receive a bonus factor of e = 2.718 . . . and will be published as the official solution at the web page. If there are several equally good “best solutions”, this bonus factor can be shared (for instance, in the case of two “best solutions”, each will get a factor of e^{1/2}). If there are other good solutions that (due to certain reasons, e.g. the usage of a significantly different approach) deserve publication, these will be also published and will receive a bonus factor of e^{0.1}\approx1.1 Chances of getting your solution published will be increased if you document your solution well, and write it down nicely (e.g. in LaTeX; a good scan of a clean hand-written work is OK, too).

There is also an additional rule for those who send many incorrect solutions before finding a correct one: if the product of all the factors (penalty and bonus) gives a number which is smaller than e^{−1}, the score e^{−1} is used, instead.

**Publication of results, awards and diplomas**

The names and results of the students with the best scores are published on the web page; the list is updated weekly, on Sundays. Diplomas will be sent by e-mail. Everyone who has solved correctly at least one problem will get a certificate of a successful participation. Platinum, gold and silver awards (thermos flasks with Physics Cup logo) will be distributed either through EuPhO/IPhO participants and team leaders, or if that deems to be impossible, by mail. Bronze awards (T-shirts with Physics Cup logo) will be distributed either through EuPhO/IPhO participants and team leaders; if that does not work out, you can get your T-shirt whenever you (or friend of yours) happen to visit TalTech.

**What you need to derive** and what you donʼt need to derive in your solutions: you can use the basic formulae related to the topics of IPhO Syllabus without proof, but everything which goes beyond that needs to be derived.